With its $45 billion buyout of the former TXU Corp. on the precipice of bankruptcy, one might think private equity giant TPG had its fill of energy deals.

But the Fort Wort Worth firm has agreed to pay Canadian natural gas company Encana $1.8 billion for a field in Wyoming with 1.5 billion of proven cubic feet equivalent, Bloomberg News reported Monday morning.

TPG, which has $59 billion under management, made a wrong way bet on natural gas prices in 2007 when it agreed with KKR & Co. and Goldman Sachs Capital Partners to buy Energy Future. You know the story, the shale drilling boom brought gas prices crashing down and with them Texas power prices.

Gas is still trading below $5 per BTU. And with much more domestic gas to be drilled few expect it to go much higher anytime in the foreseeable future.

But TPG, which for each Energy Future deal has many more winners, seems to be more optimistic.